Lin Yiyang, Han Xue, Huang Jianbin, Fu Honglan, Yu Cailan
Beijing National Laboratory for Molecular Sciences, State Key Laboratory for Structural Chemistry of Unstable and Stable Species, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, People's Republic of China.
J Colloid Interface Sci. 2009 Feb 15;330(2):449-55. doi: 10.1016/j.jcis.2008.10.071. Epub 2008 Dec 6.
A simple and effective route to design pH-responsive viscoelastic wormlike micelles based on commercial compounds is reported. According to this route, pH-sensitive viscoelastic fluids can be easily obtained by introducing a pH-responsive hydrotrope into a surfactant solution. In this paper, the mixed system of cetyltrimethylammonium bromide (CTAB) and potassium phthalic acid (PPA) was studied in detail. This pH-sensitive fluid can be switched between a gellike state and a waterlike state within a narrow pH change. Rheology and DLS results revealed that the pH-sensitive flowing behavior was attributed to the microstructure transition between wormlike micelles and short cylindrical micelles. Combined with fluorescence anisotropy, NMR, and UV-vis, it was demonstrated that the pH response of viscoelastic fluid originated from the different binding abilities of hydrotrope to surfactant as pH varies. Furthermore, different kinds of hydrotropes can be utilized to prepare pH-responsive viscoelastic fluids in the desired pH areas.
报道了一种基于商业化合物设计pH响应性粘弹性蠕虫状胶束的简单有效途径。按照该途径，通过将pH响应性助溶剂引入表面活性剂溶液中，可以轻松获得pH敏感的粘弹性流体。本文详细研究了十六烷基三甲基溴化铵（CTAB）和邻苯二甲酸钾（PPA）的混合体系。这种pH敏感流体可以在狭窄的pH变化范围内在凝胶状状态和水状状态之间切换。流变学和动态光散射结果表明，pH敏感的流动行为归因于蠕虫状胶束和短圆柱形胶束之间的微观结构转变。结合荧光各向异性、核磁共振和紫外可见光谱，证明了粘弹性流体的pH响应源于助溶剂与表面活性剂在不同pH值下的不同结合能力。此外，可以利用不同种类的助溶剂在所需的pH区域制备pH响应性粘弹性流体。
